Autofocus
Sharp focus is critical for high quality astronomical images. Focus generally needs to be adjusted throughout the night due to equipment flexure and different orientations and temperature changes. Autofocus algorithms measure image star half flux diameters (HFD) at various focuser positions and determine the optimum focus point by curve fitting.
FocusMax, commercial software which runs as a plugin to MaxIM DL and is also scriptable as a COM object.